In a political sense, well, that's much more debatable. The problem there is that because the US itself did not feel threatened, US aid came with a price tag: the impoverishment of Britain and the demolition of the trade barriers around the British Commonwealth. US aid was on a cash-only basis until Britain had spent all its hard-currency reserves (both gold and negotiable securities). Then came the Lend-Lease agreement -- arguably the point where the US truly entered the war -- and its price tag was explicit, although unadvertised: the agreement itself contains a clause stipulating the removal of the Commonwealth's trade barriers.